unix systems programming in c

saiz66 · 10-03-2004, 08:09 PM

Hi. I have never done unix systems programming before... I am using c but I don't know how to get it to run. I have done shell programming a few days ago... so I am not sure how to get started. I basically typed up a simple hello message in c in a text editor in unix. I did a "chmod u+x t" and a "./t" when it runs it gives me an error about my "int main()" Does somebody know what i am doing wrong? Thanks!

Tinkster · 10-03-2004, 08:37 PM

You did compile it, though? Or are you trying to run the source?

Cheers,
Tink

saiz66 · 10-03-2004, 08:40 PM

not sure what you mean... but how would you run a c program in unix?

Tinkster · 10-03-2004, 08:53 PM

C is a compiled language ... typing it in, and
saving the text-file doesn't make it an executable,
it's just a source file.

Typically you'll save it as test.c (or another name
with the c extension) and then run
gcc test.c -o test
gcc will automatically make test and executable.
./test will run it.

Cheers,
Tink

saiz66 · 10-03-2004, 10:35 PM

thanks a lot... and is that the same as creating a unix program? (sorry if my qustions are too vague)

Tinkster · 10-03-2004, 10:51 PM

They are indeed ... there is no such thing as
"a Unix program" ... it's either source (which needs
to be compiled on the target platform [yes, I know
there's C interpreters, but that's not the point of this])
or a script (which is interpreted on the fly, e.g. a
bash- or perl-script [yes, I know that there are
perl compilers, but that's not the point of this])

By "creating a Unix program" you could mean
writing source code of some sort or the process
of compiling some source ...

Cheers,
Tink

max_sipos · 10-03-2004, 11:42 PM

Hi, check out

www.advancedlinuxprogramming.com

Don't let the name of the book dissuade you, the first chapters are very basic.
Best wishes for your adventure in unix programming.

saiz66 · 10-04-2004, 09:16 AM

i'll give you an example to help you... I have to write a unix program that searches the specified key word and replaces each occurrence of the key word in the file with the specified new word. The key word, the new word, and the file name must be given as arguments. So I was thinking that it would be like "search word filename" as the command... not telling me how to do it.. could you just tell me how I would compile and run it... also I have to write it in the C language. Thanks!

max_sipos · 10-04-2004, 09:57 AM

http://www.advancedlinuxprogramming....with-linux.pdf

see section 1.2 - compiling with gcc

saiz66 · 10-04-2004, 10:04 AM

thanks a lot max.. when you gave me the link of the book, i thought i had to buy it.. didn't know i could view or download it.. thanks.